body {
    margin: 0;
    background: url('https://picsum.photos/800/600?grayscale') center/cover;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    color: red;
    text-align: center;
    font-family: sans-serif;
}
.container {
    background: rgba(0,0,0,0.7);
    padding: 2rem;
    border-radius: 10px;
}
button {
    padding: 0.5rem 1rem;
    background: red;
    color: white;
    border: none;
    cursor: pointer;
}